Thureophoroi or Peltastai?

[Connacht]

Peltastai Makedonikoi are Peltastai only by name. They are elite shock infantry and thus their battlefield function differs quite heavily from that of the actual Peltastai.

If I remember correctly, they were formerly called "pheraspidai", I wonder why they have been renamend "peltastai makedonikoi" even if they aren't peltastai.